Mesenchymal stem cells in the bone marrow have the ability to differentiate into various cells such as osteocytes, chondrocytes, adipocytes and myocytes, and their application to regenerative medicine for bone injury, osteoarthritis, osteoporosis, myopathy, etc. is expected. Further, it has been also revealed that mesenchymal stem cells are effective for preventing the adverse effect of bone marrow transplantation (graft-versus-host disease). Thus, like hematopoietic stem cells, mesenchymal stem cells are most close to application; a part of them has been already applied to clinical medicine (Non-Patent Document 1).
Under circumstances, development of techniques for preparing and growing mesenchymal stem cells has been attempted (Patent Documents 1 and 2)
To date, FGF-2 (Non-Patent Document 2), HB-EGF (Non-Patent Document 3) and CYR61/CCN1 (Non-Patent Document 4) have been found as growth factors for mesenchymal stem cells, but other effective factors have not been known.    [Patent Document 1] Japanese Unexamined Patent Publication No. 2004-089095    [Patent Document 2] Japanese Unexamined Patent Publication No. 2004-242619    [Non-Patent Document 1] Nikkei Biotechnology & Business, Nikkei Business Publications, Inc., July 2004 issue, pp. 16-17    [Non-Patent Document 2] Biochemical and Biophysical Research Communications 288, 413-419 (2001)    [Non-Patent Document 3] Blood 106, 59-66 (2005)    [Non-Patent Document 4] Protein Expression & Purification 42, 219-225 (2005)